I'm a .Net developer that has recently started working in the Java/GWT/Google Apps ecosystem, and honestly have found Eclipse Helios to be a perfectly good IDE.

I'm a .Net developer that has recently started working in the Java/GWT/Google Apps ecosystem, and honestly have found Eclipse Helios to be a perfectly good IDE. I can't honestly think of anything that it is missing - it has a unit test runner, "intellisense", easy dependency management etc. Eclipse also has some neat plugins like eclimd that let you run genuine vim inside the IDE.